Photo-electric musical instrument



Oct. '16, 1934.

E. SPIELMANN PHOTO:-ELECTHIC MUSICAL INSTRUMENT Filed July 23. 1951 2 Sheets-Sheet l INVENTOR. Emu'ich Spiclmrm ATTORNEYS.

1934; E. SPIELMAVNN 5 PHOTO-ELECTRIC MUSICAL INSTRUMENT Filed July 25, 1931 2 Sheets-Sheet 2 INVENTOR.

V I j r E'nzeric/y Spiellnanlz BY'WMM ATTORNEYS.

Patented Oct. 16, 1934 PHOTO-ELECTRIC MUSICAL INSTRUMENT Emeri'ch Spielmann, Vienna, Austria Application July'23, 1931, Serial No. 552,756 In Austria December 11, 1930 7 Claims. 7

This invention relates to the. photo-electric musical instruments of the .type described in U. S. Patent No. 1,778,374 and comprises improvements in these instruments.

In these musical instruments the sounds from which are given out through loud speakers or the like to which exciting currents modulated at audible frequency are supplied, the audible frequency modulation is effected by means of rotatingcircu lar discsof opaque material in which, preferably in several zones, at regular intervalsapertures or the like are providedwhich are allowed to co-operate as screens with beams of light which are-projected from light sources controlled by operating a keyboard to a photo-electric cell. The pitch is then obtained simply from the speed of rotation of each disc and the number of regularly arranged apertures for the annular zone in question. What is commonly referred to as the tone colour of a sound depends on the form or shape of the apertures, which form or shape, therefore, will be shortly referred to in the following as tone figure. Hitherto, in order to meet the requirements of a variation of tone colour with such musical instrumentsfseveral rotating screens or discs with the same tone sequences and differently shaped ap ertures or the like have been used to be selectively'operated as desired. In such electrical musical instruments, moreover, special arrangements are required in order to select and make use of any one of the rotating members, of which there is always a large number. The construction of such electrical musical instruments is obviously complicated and it has also been found to be a disadvantage that even when numerous rotating members are used for each tone sequence the tone colour can only be varied in steps.

The present invention comprises an improved arrangement of such musical instruments, which makes possible quite satisfactory playing and controlling thereof. The arrangement according to the invention consists in this that for automatic playing of photo-electric musical instruments, the circuit of the light source for each tone of this instrument, or the illumination for each tone, is automatically preferably electrically switched on or made effective by one or more contacts or the like for the tone in question being actuated for the period during which the tone is to be sounded by a member which is moved, and

- is provided with counter contacts arranged according to the tones to be played. In a preferred form ofthe invention several contacts are provided for each tone which produce different lning with insulating colours, varnish or the like.

The invention also consists-in the variation of the tone quality in photo-electric musical instruments by the introduction of screens which allow the rays from the light source for a particular 70. tone to reach the photo-electric cell either only through the openings or the like of the annular zone of the rotating circular disc corresponding to this tone, or also through the openings of one or several or all of the other annular zones of the same disc.

The invention also consists in the production of a tremolo or vibrato. of the tone or sound by, periodically interrupting or weakening the light or cell current, for example, by interposing a rotating interrupter or resistance. The tremolo can also be produced automatically by means of a contact space on the automatic playing device provided with suitable interrupting strips, or by constructing one of the resistances of the automatic playing device for regulating the intensity of the sound as rotating interrupter or resistance.

The invention also consists in a device for continuous variation of the tone colour of the sounds to be produced in photo-electric musical instruments, in which at least two synchronously rotating circular discs of opaque material, have their effective zones in the path of beams of light going from a light source to a photo-electric cell, and their corresponding zones have the same number of apertures asv operative elements in uniform division, and the shape of the aperture in one disc is different from the shape of apertures in the other disc, and the currents'produced by these discs of equal frequency and different modulation are supplied to the reproducing device (loud speaker) which is to be excited by them together, through devices for altering their relative 105 strengths at will'between predetermined limiting values.

All the parts which are, essential for understanding the invention are illustrated diagrammatically in the accompanying drawings.

Fig. 1 is a diagrammatical perspective view or the whole arrangement with keyboard.

Fig. 2 shows diagrammatically in perspective a part of the arrangement in the case in which sound is to be produced with one or with the other tone colour.

Fig. 3 shows diagrammatically in perspective an arrangement for automatic play ofa photoelectric musical instrument, and in the front part shows the contact arrangement in the fundamental simple constructional iorm, while the rear 'partshowshow'the arrangement for varying the regularly arranged apertures in the same numher and different shape, that is, diiferent tone figure. trated, the rotating members are discs of which one contains in three annular zones16, 8 and 4 triangular, and the other in the corresponding annular zones the same number of elongated holes-..) With these holes the two rotatable discs 1a and 1b project into the path of beams of light coming from incandescent lamps fl, f2, 13, if necessary through screens 4 to photo-electric cells 5a, 5b, which thus are intermittently illuminated when the. discs. in and 1b rotate. The source of current 6b is arranged in common to both photo-electric cells 5a and 5b; and for each of ,these photo-electric cells is also arranged the primary winding 7a or 7b of a transformer 7 or 7". The secondary windings 7c, 7d of these two transformers are connected in series and the secondary winding 7c is shunted by the regulable resistance 8a and the secondary winding 7d by the regulable resistance 8b.- Further, the free ends of the secondary windings 7c and'ld are connected with the input terminals of an amplifier 18 interposed before the load speaker (not wheel 9a, and thelsliding arm of the resistance 8b with a toothed wheel 9b. The toothed wheels 9a and 9b engage with a third toothed wheel 9c which is rigidly connected with an operative lever 10. The arrangement is such that the resistances 8c and 8b are varied in opposite directions without altering the sum 01' their eilfective values, that is, in the limiting position of the lever 10 either one or other of the two resistances is used at its maximum value.

, In playing the diagrammatically illustrated photo-electric musical instrument by pressure on the keys of the keyboard 151, 15:, 153 etc., the desired light source 11, f2 etc. can be brought into operation. In this case its light always falls together on the efiective zones of the'two rotating perforated discs in and 1b which thus act as screens, a sound being generated, the tone colour of which is a mixture of two difierent tone colours.

In this way the shape of the apertures in the eflective zones of the rotating discs in and 1b, as

already mentioned above, may also be referred to In the constructional example illusas tone figure. By adjusting the lever 10 the relative strengths of the individual currents supplied to the amplifler18 from the secondary winding 7c and 7d and thereby also the total tone colour can be varied as a result 0! the proportions of the tonecolour components produced by the individual rotating discs or their apertures. Ex-

perience has shown that such a variation is recognized by the human ear as a constant tone colour variation. g

In Fig. 1 also the variation of the tone character in photo electric musical instruments by the co-operation of screens is illustrated. It, for example, thelight source h is switched on by pressing the key 151 or the like, its light passes mainly through the sixteen apertures or the like of the outer annular zone which'lies nearest to it of the disc lbori to the selenium cell or the like 5b, but its light also passes through the inner zones of the disc 1b with eight or four openings to the cell 512, so that in the tone or sound produced also the tones corresponding to these zones are heard in the example chosen, that is, tones of a half and afduarter of the frequency of the tone of the marginal zone. If a screen 4 is.

provided according to the position and size of its holes, the inner zones will be more or less or wholly screened from the light source, for example, f1, so that'the tone character 01' the tone or sound produced is correspondingly altered.

In order to produce a tremolo or vibrato of the tone or sound by moving the switch 14 from the contact 14a to the contact 14b, a rotating interrupter or/resistance 12, which is driven from the same shaft 11 as. the discs 1a and 1b, is interposed in the circuit of the lamp, for example h, concerned, so that the current supplied from the battery fia is periodically interrupted or weakened, the result-of which is a tremolo in the tone produced.

In Fig. 2, two rows. of lamps fr", h etc. and 11'', New. separated by an opaque partition 18 are provided, or which the one row 11-, f1 etc. corresponds to the disc 1a, and thecell 5a and the otherirow to the disc lband the cell 51:. By pressing the key 15 the corresponding tone or sound is produced either with the tone figures of the disc 1a, or with those of the disc 1b, according to whether the switch 17 is turned to the contact 17;: or 17b.*1t the switch 1'7 is placed in the middle between the contacts 17a and 17b and is pressed down on to the lower parts of" these contacts, both lamps h and fl are switched on at the same time when the key 151 is pressed and the sound is produced simultaneously with both tone colours.

InthecaseofFig.1,aswellasinthatofFlg. 2, the sound produced can be varied in strength by the key 151 making contact with a resistance 151 by meansot a spring 151, more of the resistance being short circuited when the key is pressed 7 I automatic playing e1, er etc. The contacts 11, m, e: and so on in the constructional example illustrated, are formed by discs or strips separated from one another by insulated layers which form a comblike contact block. The closing of the contacts d-sr, d-e: etc. for producing the sound is effected by means of a band k, which can be rolled up orfolded together and moved under the contact block which is pressed against the contact block by a roller 0 of preferably elastic material. This band It consists of a conductive material, or at least a material which-is conductive on its surface, for example of so-called silver paper, and is covered on this surface with an insulating layer with the exception of its marginal strips n and the parts m which are arranged according to the sounds to be produced; so that when such a part 111. passes under the appropriate contact, for example e: the circuit of the light source for example the lamp f: is closed by the conducting bridge n-m of the band It over the contacts d, e, as is readily seen from Fig. 4 which shows a diagram of the contact arrangement for two tones, for example c and c sharp.

In the constructional example illustrated in the rear part of Fig. 2, two contacts e1 and er, .ea and e: etc. areprovided for each sound. Each of the two contacts of each sound, for example e1 and c1 is connected with the light source, for example the lamp {1 for the sound in question through a resistance of different size 91 or 91, so that according to whether the light source circult for the tone concerned is closed through the contact e; or e1 the light source acts with less or greater strength of'light and consequently also the corresponding sound is produced with less or greater intensity. With a suitably broader contact space m on the band It, both contacts e1 and e1 would be connected simultaneously, in which case on account of.the further change of resistance in the lightsource circuit, a corresponding further alteration of the sound intensity is obtained, as is shown diagrammatically in Fig. 5. The number of contacts arranged for each individual sound with diiierent resistances can of coursebe increasedas desired, and thereby the number of the resistance combinations obtainable in the light source circuit can be increased as desired so that there is a very large possibility of varying the intensity of the sound produced.

In the constructional form illustrated in the middle part of Fig. 3, two contacts e1 and e1 e2, ez etc. are provided for each sound. Each of the two contacts of each sound, for example e1 and 81 is connected with the battery (it: through a lamp of the series f1, f2 etc. and I1, fa etc., for example f1 and ii", so that according to whether the light source circuit for the sound in question is closed through the contact e1 or e1", the one or the other light source is switched on and consequently one disc la or the other lb comes into operation and thereby also the corresponding sound is produced with the one or the other tone colour. With a suitably appropriate contact place m on the band 70, both contacts er and ei can be connected simultaneously, so that the sound concerned can be produced at the same time with the two tone, colours corresponding to the different tone colours of the disc la able tone combinations can be increased as desired, so that a very large variability of the tone character of the sounds to be played, that is, a plentiful instrumentation is made possible.

By means of the arrangement for automatically playing photo electric musical instruments the above mentioned tremolo or vibrato of the sound may also be produced automatically according to the indications on the note band, either by the appropriate contact space m being provided with a suitable number of interrupting strips, or by one of the resistances gr, g1 etc. being constructed as a rotatingl'nterrupter or rotating resistance like the resistance 12 in'Fig. 1.

What I claim is:

1. A photo-electric musical instrument having at least two synchronously rotating circular discs of opaque material, annular zones of perforations in the discs, sources of light, photo-electric cells which the light reaches after passing through the discs, the discs having in their corresponding annular zones the same number of apertures in uniform distribution, and the shape of the apertures in each disc being different from that in the other discs, and means fo supplying the currents of equal frequency and different modulation produced by these discs to a reproducing device which is to be excited by them together, and, at the same time, varying their relative intensities within predetermined limits for the purpose for varying the tone colour of the sounds to be produced.

2. A photo-electric musical instrument as claimed in claim 1, in which the means for varying the relative intensities of the differently modulated exciting currents of the reproducing device comprises at least two transformers with their secondaries connected in series, and a regulable resistance connected across each secondary winding.

3. A photo-electric musical instrument as claimed in claim 1, in which the means for varying the relative strengths of the differently modulated exciting currents of the reproducing device comprise at least two transformers with their secondaries connected in series, and regulable-resistances connected across the second-,

ary windings, the movable 'parts'of the regulable resistances being connected together in a forceclosed manner.

4. A photo-electric musical instrument as claimed in claim 1, in which the means for varying the relative intensities of the differently modulated exciting currents of the reproducing device comprises at least two transfonners with their secondaries connected in series, and a regulable resistance connected across each secondary winding, having rotatable sliding contact arms on the regulable resistances, a toothed wheel rigidly connected with each sliding contact arm, and a toothed wheel secured to the adjusting lever engaging with the other toothed wheels.

5. A photo-electric musical instrument as claimed in claim 1, in which the means for varying the relative intensities of the differently modulated exciting currents of the reproducing device comprises at least two transformers with their secondaries connected in series, and a regulable resistance connected across each secondary winding, the resistance being variable together in opposite directions without altering the sum of. their effective values 6. A photo-electric musical instrument an individual light individually operatable for each sound, rotating discs with annular zones of perforations, the nmnber of perforations in each zone difiering from those of its neighboring zone as multiples of two characterized in that there is arranged between lights and perforated dlsm a movable geared screen which, when engaged, will direct the light of any light only upon one annular' zone; while permitting the light to strike all annular zones when disengaged.

7. A photo electrlc musical instrument as claimed in claim 1 having for each sound a. separate electric lamp which is separately operated, an electric circuit for said lamp, means to close said circuit to light said lamp, and means in said circuit for varying the intensity of light from said lamp.

: EMERICH SPIELMANN. 

